A Donald Trump presidency is among the greatest threats facing America, and the Republican standard-bearer is the worst major-party candidate for the job in U.S. history.

In the nearly half-century history of Foreign Policy, the editors of this publication have never endorsed a candidate for political office. We cherish and fiercely protect this publication’s independence and its reputation for objectivity, and we deeply value our relationship with all of our readers, regardless of political orientation.

It is for all these reasons that FP’s editors are now breaking with tradition to endorse Hillary Clinton for the next president of the United States.

Our readers depend on FP for insight and analysis into issues of national security and foreign policy. We feel that our obligation to our readers thus extends now to making clear the great magnitude of the threat that a Donald Trump presidency would pose to the United States. The dangers Trump presents as president stretch beyond the United States to the international economy, to global security, to America’s allies, as well as to countless innocents everywhere who would be the victims of his inexperience, his perverse policy views, and the profound unsuitability of his temperament for the office he seeks.

The litany of reasons Trump poses such a threat is so long that it is, in fact, shocking that he is a major party’s candidate for the presidency. The recent furor over his vile behavior with women illustrates the extraordinary nature of his unsuitability, as does his repudiation by so many members of his own party — who have so many reasons to reflexively support their nominee.

Beyond this, however, in the areas in which we at FP specialize, he has repeatedly demonstrated his ignorance of the most basic facts of international affairs, let alone the nuances so crucial to the responsibilities of diplomacy inherent in the U.S. president’s daily responsibilities. Trump has not only promoted the leadership of a tyrant and menace like Vladimir Putin, but he has welcomed Russian meddling in the current U.S. election. He has alternatively forgiven then defended Russia’s invasion of Crimea and employed advisors with close ties to the Russian president and his cronies. Trump has spoken so cavalierly about the use of nuclear weapons, including a repeated willingness to use them against terrorists, that it has become clear he understands little if anything about America’s nuclear policies — not to mention the moral, legal, and human consequences of such actions. He has embraced the use of torture and the violation of international law against it. He has suggested he would ignore America’s treaty obligations and would only conditionally support allies in need. He has repeatedly insulted Mexico and proposed policies that would inflame and damage one of America’s most vital trading relationships with that country.

Trump has played into the hands of terrorists with his fearmongering, with his sweeping and unwarranted vilification of Muslims, and by sensationalizing the threat they pose. He has promised to take punitive actions against America’s Pacific trading partners that would be devastating to the world economy and in violation of our legal obligations. He has dismissed the science of climate change and denied its looming and dangerous reality. He has promoted a delusional and narcissistic view of the world, one in which he seems to feel that the power of his personality in negotiations could redirect the course of other nations, remake or supplant treaties, and contain those tyrants he does not actually embrace.

He has repeatedly denigrated the U.S. military — its leadership, service members, veterans, and the families who stand behind them. He has also derided the intelligence community. Many of the most prominent Republican national security and foreign-policy specialists have repudiated him publicly. Indeed, he is not simply seen as a dangerous candidate by members of the Democratic Party, but virtually no single credible GOP foreign-policy advisor has joined his team. This is because Trump either undercuts or has placed himself in opposition to the best foreign-policy traditions of the Republican Party and to the standards and ideals of every GOP administration in modern history.

There are other reasons to oppose Trump. He has repeatedly demonstrated a complete disregard for America’s most important values, from tolerance to respect for the rule of law.

He has treated the press with derision, demeaning individual reporters, and his campaign has employed exclusionary policies that targeted specific news organizations, suggesting a complete disregard for the First Amendment to the U.S. Constitution. He has shown such a complete disregard for the truth that he has arguably done more than any other single individual to seek to usher in a new and unwelcome post-fact era in America’s political debate. That is not just odious but if it becomes more accepted could compromise and undercut governance in the United States for generations to come. His proposed policies on immigration and for dealing with Muslims in America show scorn for the Fourth Amendment. Based on a lifetime of statements and actions, Donald Trump has revealed himself to be a racist and, again and again, a misogynist. Throughout this election he has cynically embraced the support of white supremacists and anti-Semites.

He would therefore put at risk our way of life, our freedoms, and our alliances. His reckless behavior has already undermined America’s standing internationally. His proposed embrace of some bad actors and his provocations toward others, his dangerous views on the use of weapons of mass destruction, his failure to understand how the global economy works, his lack of appreciation for the importance of alliances, and his temperamental defects all suggest that were he to claim the Oval Office, he would be a destabilizing force that would undercut American leadership instantly and for generations to come. His spotty track record as a businessman compounds these flaws further still.

Indeed, we are not the first to say it, but Trump is the worst major-party candidate this republic has ever produced.

Fortunately, not only is Trump opposed by a worthy candidate, but his opponent is, on foreign-policy and national security issues — all of the areas we cover here at FP — one of the best qualified candidates this country has produced since World War II. As first lady, New York senator, and secretary of state, Hillary Clinton regularly distinguished herself by her intelligence, dogged work ethic, ability to work across the political aisle, and leadership on difficult issues. She has devoted her entire life to public service and has been a powerful and effective advocate for women, children, and those in need at home and abroad. Whether you agree with all the policy stances of her campaign or not, impartial eyes will conclude that her proposals on climate change, combating terrorism, and human rights are thoughtful and comprehensive — and ultimately worthy of consideration.

Hillary Clinton is a quality candidate who is unquestionably well-prepared to lead this country. What is more, we do not think it is a small thing that by her election she will be righting a deep wrong that has compromised U.S. democracy since its inception: the exclusion of women from its highest offices. Were she to be elected as this country’s first woman president, not only would it be historic and send an important signal about both inclusiveness and Americans’ commitment to electing candidates who have distinguished themselves on their merits, but she would enter office having already put down one great threat to the United States of America — the grotesque and deeply disturbing prospect of a Donald Trump presidency.